Room-temperature, solution-processable organic electron extraction layer for high-performance planar heterojunction...

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Perovskite solar cells (PVSCs) are a promising photovoltaic technology.
• High-performance PVSCs often rely on complex, high-temperature processed interlayers.
• Developing efficient, low-temperature processed electron extraction layers (EELs) is crucial for scalable manufacturing.

Purpose of the Study:

• To introduce a room-temperature, solution-processable organic EEL for planar heterojunction perovskite solar cells (PHJ PVSCs).
• To investigate the performance and mechanism of a novel bilayered EEL composed of fulleropyrrolidinium iodide (FPI)-polyethyleneimine (PEIE) and PC61BM.
• To demonstrate the potential of this EEL for high-performance flexible PVSCs.

Main Methods:

• Fabrication of a bilayered EEL using FPI-PEIE and PC61BM.
• Characterization of the EEL's effect on perovskite crystallization and charge extraction.
• Performance testing of rigid and flexible PHJ PVSCs incorporating the novel EEL.
• Analysis of work function tuning and doping effects of the EEL components.

Main Results:

• Achieved a power conversion efficiency (PCE) of 15.7% for rigid PHJ PVSCs with insignificant hysteresis.
• Demonstrated that PC61BM acts as a surface modifier, improving perovskite crystallization and charge extraction.
• Showcased efficient electron transport facilitated by FPI-PEIE's work function tuning and PC61BM doping.
• Successfully fabricated high-performance flexible PVSCs with a PCE of approximately 10%.

Conclusions:

• The FPI-PEIE/PC61BM bilayer serves as an effective organic EEL for high-performance PVSCs.
• Room-temperature processed organic EELs offer a viable alternative to transition metal oxide interlayers.
• This technology enables the development of highly printable and compatible PVSCs with excellent performance.